During his 32 years of service Colonel Crozier served continuously in aviation and infantry units from company through brigade levels. He commanded the 76-aircraft 101st Aviation Company, that utilized the Army's first UH-1As for field testing, a unit that was later reorganized into the Army's first aviation battalion.

His Company was the first to demonstrate troop-rappelling from the UH-1A, to use multiple refueling points, and to use camouflage-painted UH-1As. The 101st Aviation Battalion (Prov) became the model for future battalions in SOPs, ATTs, etc.

As a LTC(P), Crozier was selected to command and reorganize the division's aviation assets along with the USARV assets into the 160th Aviation Group (later the 101st Aviation Group), while maintaining its combat commitments to include the five-division assault into the Ashau Valley. This one-year task took six months and included a successful Command Maintenance Management Inspection. During this period the 101st Airborne Division (AASLT) was selected as AAAA's "Aviation Unit of the Year."

He then became Chief of the 16,000-member Aviation Warrant Officer Branch, his many innovative approaches improving many aspects of AWO management. Later, he served as President of the Army portion of the DoD Close Air Support Study, which prevented the Army's attack helicopters from being placed under USAF command and control.

The first Aviator to serve as Chief of Staff of the 101st Airborne Division (AASLT), he was responsible for all facets of training and the 101st's deployment to Europe for REFORGER 1976. Crozier still serves the 101st as the first "Honorary Colonel of the 101st Aviation Regiment.